Apparatus for the desiccation of substances



Mamh W W33. F. H. DOUTHITT APPARATUS FOR THE DESICCATTON OF SUBSTANCES 'Filed June 27, 2 Sheets-Sheet 1 March 317, 1931- F. H. DOUTHITT APPARATUS FOR THE DESICCATION OF SUBSTANCES Filed June 1927 2 Sheets-Sheet 2 Patented .Mar. 17, 1931 UNITED STATES PATENT OFFICE FRANK HOWARD DOUTHITT, OF CHICAGO, ILLINOIS, ASSIGNOR OF ONE-HALF TO CHESTER EARL GRAY, OF OAKLAND, CALIFORNIA APPARATUS FOR THE DESICCATION OF SUBSTANCES Application filed June 27,

This invention relates to improvements in ap aratus for the desiccation of substances an more particularly to improvements in apparatus for the desiccation of substances as set forth in United States Patents No.

1,078,948 and No. 1,107 ,794 and United States application No. 78,313, filed December It has been found, however, that much more effective and uniform results can be obtained by the improved construction hereinafter described of the openings for the admis sion of the treating medium into the drying chamber.

With such an object, the main feature of novelty of the present invention consists in A series of converging tangentially-disposed slot-like nozzles divided by suitable partitions operable from Without the apparatus for the delivery and control of the treating medium issuing into the drying chamber.

Various forms of apparatus will naturally suggest themselves to those skilled in the art once the invention is understood and, therefore, it is not intended that the present application should be limited to any particular form of construction. The accompanying drawings, therefore, represent an example of the apparatus which is particularly adapted to give good commercial results in the drying of milk.

Referring now to the drawings in which like characters of reference indicate corresponding parts in each figure,

Fig. 1 is a general View of the apparatus as a whole, principally in sectional elevation.

Fig. 2 is a section on the line 22 of Fig. 1.

Fig. 3 is. a section on the line 3-3 of Fig. 1.

Fig. 4 is a sectional detail showing the means for adjusting the openings from the wind box into the drying chamber.

In the example of my apparatus as described, A designates the drying chamber and B the collector. Thelliquid to be treated is first introduced into a supply tank 10 of any suitable form and here shown as a wooden vat suitably lined to preserve the contents. Leading from this tank is a delivery pipe 11 connected to a centrifugal pump 12 which delivers into a heating device 13, the character 1927. Serial N0. 201,847.

of which more or less depends on the liquid or substance being treated. VVhen', as in the present instance, milk is being treated the device 13 may be a heater and a pasteurizer. It may, on the other hand, be in the form of a cooler or may under certain conditions be dispensed with altogether.

From the heater 13 a pipe 14 leads back into the supply tank 10 whereby, in operation,

a continuous circulation is provided.

Connecting the delivery pipe 11 with a centrifugal pump 15 is a branch pipe 16 while a control valve 17 is provided in the pipe 11. The centrifugal pump 15 is connected through a pipe 18 provided with a manually operable Valve 19 and adjacent its upper end is connected with a pipe 20 communicating with the centrifugal pump 21, the pipe 20 communicating at its other end, as at 22, with a discharge in the bottom of the collector B and the centrifugal pump 21 connecting through a pipe 23 with a heater 24, which is in turn connected through a pipe 25 to a vertical pipe 26 within the collector and on which, adjacent the top, is rotatably mounted a horizontal pipe 27 provided with a plurality of nozzles 28 from which the liquid under treatment issues in jets. The end of the vertical pipe 26 is supported as at 29 on a cross bar 30 in the exhaust conduit 31 of the collector B. A branch pipe 32 valve controlled as at 32a leads fromthe pipe 25 into the collector and a valve (not shown) may also be provided in this pipe, whereby the proportion of liquid which will flow up the pipe 26 is regulated to wash the exhaust moisture-laden air from the drying chamber A before being discharged through the collector conduit 31 and whereby any dried particles escaping from the drying chamber A are entrapped and moistened to be brought down into the liquid in the collector and reheated on the way to the drying chamber, thus ensuring that nothing in the way of solids can possibly escape and that the moistened air exhausted from the collector B contains nothing but moisture. A circulation system and return is thus automatically provided for the liquid or substance being dried.

For automatically regulating the supply of liquid to the collector or spent gas washer B, I provide a float 34 mounted on a sleeve 35 vertically slidable above the lower end 36 of the pipe 26 which forms a guideway for the float. The sleeve 35 is provided with an arm 37 liingedly connected thereto and having spaced loops 38 adapted to slidably engage with an arm or rod 39, to the outer extremity of which is connected a chain 40 in turn connected to a valve 41 in the pipe 18.

By means of the float 34 the height of the liquid Within the collector B is automatically controlled, as when the liquid rises the float moves upwardly with the sleeve 35, causing the chain 40 to slacken, permitting the valve 41 to close. Then as the liquid recedes, the float 34 travels downwardl causing tension of the chain 40 to open the valve 41 and thus permit the flow of liquid into the collector.

Communicating with and attached to the collector B is a settling device or container 42, of any suitable size and shape, into which the liquid from the collector may pass and settle after reaching a certain level. The container communicates with the lower end of the collector by means of the pipe 43 which is provided with a regulating valve 43a. The pipe line 44 connecting the base of the container 42 and the high pressure pump 45 is provided with a valve 46 by which means the settling device may be shut off at will and dispensed with.

From the foregoing it will be seen that the liquid in the supply tank 10 is first heated and pasteurized by means of the supply pipe 11, centrifugal pump 12, heater 13 and return pipe 14. It is then pumped by the centrifugal pump 15 through pipe 18 and pipe 20 to pump 21, from whence it is pumped through the heater 24 and through the branch pipe 33 into the collector and also into the pipe 26 and nozzle-carrying pipe 28, Where the liquid level is automatically regulated by the float 34, operating the valve 41, to shut off the supply to the pipe 18, on a predetermined quantity of liquid being received in the collector B. The discharge of liquid from the collector B may be through the settling tank 42, through valve controlled pipe 43, or directly through pipe 20, to the pipe 47, communicating with the force pump 45.

It will also be noted that the supply tan k and the other devices associated therewith, as already described, including the heater and the pumps 12, 13 and 15, are preferably located at a lower level than the collector and that for this reason in constructing the apparatus it is usual to place these members on the floor and the collector, as indicated in Figure 1, on the floor C next above.

If desired, more than one supply tank may be used with a corresponding equipment of pumps and connections.

The function of the pipe 45 is to force the heated liquid coming through the pipe 47 from the collector B, or from collector B through the settling device 42, through a pipe 48 to the spray nozzle 49, located centrally within the drying chamber A. The pipe 48 in the example shown, enters the drying chamber through a sleeve 50 which extends through a portion of the centrally arranged exhaust conduit 51 of the drying chamber which communicates tangentially as at 52 (see Figure 3) with the collector B. Thus the liquid, in this case milk, is supplied to the atomizer nozzle 49 through the pipe 48 communicating with the high-pressure pump 45 driven from any suitable source of power and adapted to maintain a high and uniform pressure.

By means of the settling device 42 the liquid supplied to the pump 45 from tank 42 will be of greater density than if unsettled from the collector, thereby ensuring more efi'ective and uniform operation of the pump 45 through the reduction of air bubbles in the pipes, and eliminating the necessity for a booster to overcome this condition. With the settling of the liquid supply the pump 45 functions more efficiently and provides a uniform, instead of an intermittent, spray through the nozzle 49.

It will readily be understood the more regular the action of the pump 45 the more satisfactory is the spray.

The drying chamber A, is preferably of conical or funnel formation cylindrical portion 53 provided with an airsupply conduit 54 (see Figures 1 and 2), communicating with which is a casing 55 containing a plurality of heating coils 56. A blower 57 communicates with this casing to deliver air under pressure thereto.

The casing 55 is also provided with a door 58 clear of the heating coils and conveniently accessible.

As more particularly illustrated in Figure 2, the cylindrical portion 53 of the drying chamber is provided with an air duct 59 peripherally spaced from the cylindrical portion, and communicating with the casing whereby, in combination with the blower 57 and the heating coils 56, hot air under pressure is supplied to the duct 59.

The essential features of this construction are a plurality of spaced tangential slots 61 extending vertically the full depth of the sides of the air duct 59 and are of greater width at the intake as at 62 than at the discharge or inner ends 63 communicating with the drying chamber. These slots 61 are vertically divided by spaced superimposed parti- 1 tions or vanes 64 extending tangentially 1nwardly and slantwise downwardly from the intake openings to form individual superimposed nozzle-shaped air or fluid discharge members whereby a tendency to descend in with an upper the heating chamber; at the bottom of the chamber, its direction changes and it rises in the center, to meet the spray from the nozzle 49 and carry it automatically to the more heated periphery Where it is uniformly desiccated almost instantly, the desiccated material falling by gravity against the sides and to the bottom of the drying chamber.

Another feature of the improved apparatus is the adjusting means for regulating the size of the passageways or slots'6l opening from the wind box into the drying chamber. An example of such means is disclosed in Figure 4 in which hingedly mounted movable vanes 91 are provided in addition to the fixed vanes or partitions 64. These movable vanes 91 may be selectively or collectively operated to regulate the size of the passageways or slots 61 and thereby control the extent of flow of fluid therethrough from the wind box into the drying chamber.

In the example disclosed the adjustable vanes 91 hingedly mounted at their inner ends as at 92 are pivotally connected at their outer ends at 93 to a rod 94 in turn connected in any suitable manner, such as by ball and socket joint, as at 95 to an operating rod 96 protruding beyond the wind box and threaded to engage with the wind box casing as at 97, the operating rod being provided with a wing nut 98.

Reverting to the adjustable vanes for the wind box, in operation when the rod 96 is rotated in one direction, the vanes 91 move upwardly, as indicated in dotted lines in Figure 4, to restrict the slots or passageways 61 and on the rod 96 beingrotated in the opposite direction the vanes 91 will assume their normal position as shown in full lines in Figure 4, lying snugly against the fixed vanes 64.

Under the foregoing conditions the air and the substances or liquid being treated both partake of a cyclonic movement, the air having imparted to it an accelerated downward movement. The cyclonic downward movement thus causes the air gradually to approach the axis while the spray gradually recedes from the center of rotation, causing the liquid or substance being treated to be discharged at the periphery, so that the humidity of the air is increased as it approaches the center and that of the liquid or substance being treated is decreased as it recedes from the center.

Furthermore, the center of the cyclonic current of air being rarified by the centrifugal force of the whirl and thereby cooled and the temperature remaining higher at the periphery, the liquid or substance sprayed is quick y subjected to the action of air which will extract from it the greatest quantity of moisture and it will, therefore, be quickly reduced to completely dry or desiccated condition. In other words, the outer zones of the whirling air in the drying chamber are, under practically all conditions, hotter than the center, as in addition to the rarification of the air towards the center, the humidity increases in proportionate proximity to this point. Therefore, the sprayed liquid is not only subjected quickly to the action of air of decreasing humidity but to the action of air of increasing temperature, so as thereby to be more effectively desiccated.

With the present construction the spray encounters a whirling vortex of air, the axis of which coincides with the vertical axis of the drying chamber, the upwardly moving central column being cooled so that the spray is subjected to the action of air which is in condition to extract from it the greatest quantity of moisture.

The substance to be treated, for example milk, is discharged centrally, through the nozzle 49, into the falling cyclonic current of heated air established in the chamber by being introduced thereinto through the tangential slots 61 forming nozzle-shaped members tapering inwardly and slanting downwardly in the air duct wall.

The atomized particles will, through the action of centrifugal force, be caused to travel outwardly to be finally arrested by the confining walls of the chamber, down which they fall to the discharge 66 in the bottom or lower end of the drying chamber A.

The improved construction of my wind box and the special formation of the tangential air openings, arranged slantwise and constricted towards the discharge, improves the effect produced by the descending vortex and enables the speed of the descent to be increased and controlled whereby the efficiency of the apparatus is materially increased.

Finally, the moisture-laden and still whirling air, with practically no solid particles in suspension passes out through the air conduit 51 connected tangentially to the collector B, which acts as a trap, or recovery chamber for the solid particles, if any, by returning them to the substance of liquid in circulation.

Furthermore, a considerable portion of the heat that is returned to this chamber through the conduit 51 would be lost if allowed to escape to the atmosphere direct.

While the heated air under pressure for the drying chamber may be at a temperature of approximately 260 F., the exhausted air through the conduit 51 will be at a temperature substantially of F. to 180 F. and asit enters the collector B it comes in contact with the jets of liquid issuing from the pipe 27 with the result that the temperature of the liquid in travel is raised, thus preheating it preparatory to issuing under pressure from the nozzle 49 and as this liquid can be allowed to settle it is not only preheated and partially condensed but also of increased density when it reaches said nozzle.

The exhaust air from the drying chamber, now moisture-laden owing to its treatment in the collector, is finally discharged through the conduit 31 at a temperature of substantially 50 to 60 degrees lower than the temperature at which it entered the collector B. It should also be noted that the air delivered from the drying chamber A to the collector B is deflected preferably in a downward direction as indicated at 65.

The powder from the drying chamber A is discharged through the opening 66 in the lower end, which communicates with a powerdriven disintegrator consisting of spirally arranged pipes and a blower 67 so that the heavier of the atomized particles will by contrifugal action be thrown to the outer wall of the spiral and there be broken up and the moisture liberated, while the lighter particles will be drawn from the inner portions of the spirals and directly up through the delivery duct 68. This duct or conduit 68 leads to traps 69 and 70 provided with suitable delivery spout. The upper trap 69 has a pipe 76 leading back to the lower end of. the drying chamber A for the purpose of returning thereto any solid particles that fail to descend from the traps 69 and 70, at the same time providing an outlet for the air currents.

Co-ordinating mechanical means are provided in the form of a sweep 77 comprising a rod 78 curved at its lower end at substantially right angles, as at 79, and pivotally mounted at 80 on a. universal joint member 81 arranged in a bearing in a cross bar 82. The rod 78 extends slantwise parallel with and spaced from the converging wall or the drying chamber and is straightened at its upper end as at 83 and there suspended by a chain 84 connected to a collar 85 mounted on a suitable bearing on the sleeve 50. A tapering vane 86 is secured longitudinally on this rod, projecting outwardly and adapted to be engaged by the whirling vortex of air whereby the sweep as a whole is continuously kept in motion around the wall of the drying chamber.

As particularly illustrated in Figure 2, lengths of chains 87 are connected to the vane more effectively to sweep the wall and remove any particles which have alhered thereto.

This construction, comprising the universal jointed support on which the sweep is pivotally mounted and the suspension means for the sweeper rod, ensures a more rapid and uniform sweeping movement of this member when the apparatus is in operation, whereby cleaning and sterilizing of the drying chamber is facilitated, as from its mounting it may be swung and bent in any direction.

The whirling air causes the sweeper to revolve, dragging the chains along the sides of the converging walls to remove any deposits thereon and allow themto drop into the discharge in the bottom of the chamber.

For observation, peep holes 88 and 89 are provided in the exhaust conduits 51 and 31, and for other purposes a manhole 90.

Recording thermometers may also be used for taking the temperatures at different periods.

Modifications may be made in the apparatus above described within the scope of the claims, without departing from the spirit or scope thereof.

\Vhat I claim as my invention is 1. Apparatus of the class described comprising a drying chamber provided with a discharge opening for the desiccated material in the bottom and an air discharge opening at the top, means for introducing into the chamber a controlled cyclonic current of moisture absorbing air by way of tangentially directed air nozzles sub-divided by vertically disposed partitions adjustable from without the chamber, the cross-sectional area of said nozzles being reduced in the direction of the,

air current to cause the axis of said current to coincide with the axis of the drying chamber, means for atomizing liquid into the cyclonic current of air within the drying chamber, and means for settling such liquid before being atomized.

2. Apparatus as claimed in claim 1 in which the air nozzles are sub-divided by appropriate inclined partitions into superimposed passageways.

3. Apparatus as claimed in claim 1 in which the adjusting means for the air nozzles include hinged vanes operable individually and collectively by suitable mechanism.

4. Apparatus as claimed in claim 1 characterized in that the adjustable means for each nozzle are interconnected.

5. Apparatus as claimed in claim 1 in which the subdividing means for each air nozzle are interconnected at their free ends 'by means of a rod adapted to be moved in a vertical direction and operable from without the chamber.

6. The invention according to claim 1 in which the subdividing means for the air nozzles consist of fixed partitions and movable vanes hingedly connected thereto the inclination of which is adjusted separately and collectively.

In witness whereof I hand.

FRANK HOWARD DOUTHITT.

have hereunto set my 

